1. Field of the Invention
The present invention relates to a table saw having an auxiliary table surface, and in particular, to the dual sliding rail mechanism for movably attaching the auxiliary table surface to the table saw.
2. Scope of the Prior Art
Table saws of various designs include a frame and an upper surface having an opening through which a blade extends. The upper surface supports a material, such as wood, as it is pushed for cutting by the blade. Table saws have traditionally been stand-alone pieces of equipment that are used in workshops or other locations. Because most stand-alone table saws are used in large open spaces, the dimensions of the table saw can be large enough to support materials of various sizes. Regardless of how large the upper surface of the table saw is, however, there have been numerous means to expand the cutting surface. These different methods include sliding tables extending from a side of the table saw, separate auxiliary surfaces that are secured to the side of the cutting surface, and a table surface that folds from any edge of the table saw.
Tables that are used in workshops are not readily moved from one location to another. At construction sites and other locales, however, it is useful to have a table saw that can be easily moved from one location to another and between different construction sites. Accordingly, smaller table saws have been designed. These table saws use lighter materials and have reduced the dimensions of the frame and the upper surface to thereby reduce the size and weight of the table saw. Thus, there now exist portable table saws. The portable table saws also use a separable folding table to support the table saw at the correct height for operation.
Even though portable table saws are used at construction sites, the need to use the saw for large pieces of material has not lessened. In order for the table saw to efficiently cut a large piece of material, such as an four-foot-by-eight-foot piece of plywood, the material must be adequately supported by the upper surface. Otherwise, less than accurate cuts will be made thereby wasting valuable materials. Accordingly, portable table saws often include an auxiliary table surface that expands the usable work space provided by just the table saw. Because the table saw must be portable, it is more beneficial to have an auxiliary table surface that is movable attached to the portable table saw. This arrangement reduces the number of parts that must be moved from one location to another and makes the portable table saw easier to use.
In addition, other types of tables utilize auxiliary table surfaces. Accordingly, there are numerous different configurations and arrangements used to connect an auxiliary table surface to the frame and upper cutting surface of a portable table saw. Various different configurations have been used to connect a detachable auxiliary table surface to a side edge of a table saw's upper cutting surface. These configurations include bolting the auxiliary table surface to the upper surface such that the side surfaces of the auxiliary table and the upper surface are adjacent to each other. Other arrangements use slots in the upper surface or frame of the table saw and tabs on the auxiliary table such that the tabs fit into the slots to attach the auxiliary table to the table saw. Screws can be used in conjunction with the tab and slot design to secure the auxiliary table in place. Similarly, auxiliary tables can be connected to the side of the upper surface so that the auxiliary table folds between an extended position to increase the size of the working surface and a lower position where the auxiliary table rests against the side of the frame. The prior art arrangements, however, do not allow the user to expand or contract the working area of the upper surface and auxiliary table depending on the size of the material being cut or the work being performed.
In other table designs, the upper surface of the table is divided into sections where one section slides on rails formed in the table frame. When the movable section is moved to an expanded position, a separate auxiliary table can be added between the sections. A corollary to that design is to have rails that can be pulled from the upper surface or frame of the table saw and then to place a separate auxiliary table surface on the rails. These configurations do not necessarily provide for mechanisms to secure the rails in any position or mechanisms to secure the auxiliary table to the rails. If such a mechanism is provided, it is not an integral part of the table. In addition, the configurations rely on the use of a separable auxiliary table surface, which can be lost or broken so that it does not fit properly on the rails.
Table saws have also been configured with rails that are attached to the front and rear edge surfaces of the upper surface. These rails extend beyond at least one side end of the table saw. An auxiliary table surface can be movable attached to the rail so that the auxiliary table moves along the rail between a position adjacent the upper surface of the table saw and a position at the end of the rails. A lever or other locking mechanism can be used to secure the auxiliary table in any position between the two end positions.
In an alternative embodiment, the auxiliary table uses a rack and pinion design to move between the adjacent position and the extended position. In this embodiment, the rails include a rack and the auxiliary table is connected to the rails by a mechanism including a knob and a pinion. As known in the art, the knob rotates the pinion so that the auxiliary table moves along the rack to a designated position. A locking mechanism can be provided on the knob and pinion mechanism to secure the auxiliary table in any position along the rail. Such a locking mechanism can include a pin or post that pushes against the rail thereby making it difficult for the pinion to move along the rack. The pin is connected to a lever so that the pin can move between a locked position and a released position. The configurations that include a rail do not efficiently reduce the size of the table saw because the rails extend from the sides of the table saw therefore not effectively reducing the overall dimensions of a portable table saw. The rails can also make it difficult to move the portable table saw because they are awkward and can catch on other materials.
The rack and pinion configuration can also be arranged so that the rail and the rack is secured to the auxiliary table such that the rotation of the pinion along the rack moves the rail and the auxiliary table between an adjacent position against the upper surface and an extended position away from the table saw. Although the rack and pinion design functions sufficiently, it requires expensive parts and materials for it to work properly. In addition, the locking mechanisms do not necessarily adequately secure the auxiliary table in a position.